I spent the last weekend in Montreal
and had the pleasure of riding the Metro, which was so shaky as to make me feel tired every time I got off it. Those trains made me need to sit down all day long.
But let's put personal opinions aside and hear some facts. The Metro's fare collection system is a bastard child of the New York and Boston systems, as far as I'm concerned. The first time I rode it, not knowing procedure, I bought a ticket from the attendant and waved it past the little slot reader.
The gate opened.
In theory, you have to drop the ticket into the magnetic reader for the gate to open -- that's certainly the idea. I didn't realize that the tickets, which I imagined worked like single use MetroCards, had the same value after use. The second time I rode the Metro, I did the same thing and was chased down in a hail of French curses by the attendant. I couldn't even figure out what I'd done wrong until later that day.
In theory, you need to buy a ticket every time you ride the Metro. In practice, the range of the ticket reader extends about half an inch (sorry, sorry, about a centimeter) past its outer wall. With a little sleight of hand, you can wave the ticket by the slot while actually palming it and get a two-for-one ride.
Of course, you have to use the ticket at one of the little vacuum-gates afterwards, so at best you're getting one free ride per paid ride. Still, not such a bad deal.